Add asynchronous posix signal handling.

Add signal tests.

asyncdispatch2.nimble

@@ -26,6 +26,10 @@ task test, "Run all tests":
   exec "nim c -r tests/testfut"
   exec "nim c -r -d:release tests/testfut"
 
+  exec "nim c -r -d:useSysAssert -d:useGcAssert tests/testsignal"
+  exec "nim c -r tests/testsignal"
+  exec "nim c -r -d:release tests/testsignal"
+
   exec "nim c -r -d:useSysAssert -d:useGcAssert tests/testdatagram"
   exec "nim c -r tests/testdatagram"
   exec "nim c -r -d:release tests/testdatagram"

asyncdispatch2/asyncloop.nim

@@ -185,6 +185,7 @@ proc initCallSoonProc() =
 
 when defined(windows) or defined(nimdoc):
   import winlean, sets, hashes
+
   type
     WSAPROC_TRANSMITFILE = proc(hSocket: SocketHandle, hFile: Handle,
                                 nNumberOfBytesToWrite: DWORD,
@@ -203,6 +204,9 @@ when defined(windows) or defined(nimdoc):
       bytesCount*: int32
       udata*: pointer
 
+    CustomOverlapped* = object of OVERLAPPED
+      data*: CompletionData
+
     PDispatcher* = ref object of PDispatcherBase
       ioPort: Handle
       handles: HashSet[AsyncFD]
@@ -211,9 +215,6 @@ when defined(windows) or defined(nimdoc):
       getAcceptExSockAddrs*: WSAPROC_GETACCEPTEXSOCKADDRS
       transmitFile*: WSAPROC_TRANSMITFILE
 
-    CustomOverlapped* = object of OVERLAPPED
-      data*: CompletionData
-
     PtrCustomOverlapped* = ptr CustomOverlapped
 
     RefCustomOverlapped* = ref CustomOverlapped
@@ -324,12 +325,6 @@ when defined(windows) or defined(nimdoc):
       var callable = loop.callbacks.popFirst()
       callable.function(callable.udata)
 
-  template getUdata*(u: untyped) =
-    if isNil(u):
-      nil
-    else:
-      cast[ptr CustomOverlapped](u).data.udata
-
   proc getFunc(s: SocketHandle, fun: var pointer, guid: var GUID): bool =
     var bytesRet: Dword
     fun = nil
@@ -497,6 +492,27 @@ else:
       raise newException(ValueError, "File descriptor not registered.")
     p.selector.updateHandle(int(fd), newEvents)
 
+  when ioselSupportedPlatform:
+    proc addSignal*(signal: int, cb: CallbackFunc,
+                    udata: pointer = nil): int =
+      ## Start watching signal ``signal``, and when signal appears, call the
+      ## callback ``cb``. Returns signal identifier code, which can be used
+      ## to remove signal callback via ``removeSignal``.
+      let p = getGlobalDispatcher()
+      var data: SelectorData
+      result = p.selector.registerSignal(signal, data)
+      withData(p.selector, result, adata) do:
+        adata.reader = AsyncCallback(function: cb, udata: addr adata.rdata)
+        adata.rdata.fd = AsyncFD(result)
+        adata.rdata.udata = udata
+      do:
+        raise newException(ValueError, "File descriptor not registered.")
+
+    proc removeSignal*(sigfd: int) =
+      ## Remove watching signal ``signal``.
+      let p = getGlobalDispatcher()
+      p.selector.unregister(sigfd)
+
   proc poll*() =
     let loop = getGlobalDispatcher()
     var curTime = fastEpochTime()

tests/testsignal.nim

@@ -0,0 +1,43 @@
+#              Asyncdispatch2 Test Suite
+#                 (c) Copyright 2018
+#         Status Research & Development GmbH
+#
+#              Licensed under either of
+#  Apache License, version 2.0, (LICENSE-APACHEv2)
+#              MIT license (LICENSE-MIT)
+
+import unittest, strutils
+import ../asyncdispatch2
+
+when not defined(windows):
+  import posix
+
+  var signalCounter = 0
+
+  proc signalProc(udata: pointer) =
+    var cdata = cast[ptr CompletionData](udata)
+    signalCounter = cast[int](cdata.udata)
+    removeSignal(int(cdata.fd))
+
+  proc asyncProc() {.async.} =
+    await sleepAsync(500)
+
+  proc test(signal, value: int): bool =
+    discard addSignal(signal, signalProc, cast[pointer](value))
+    var fut = asyncProc()
+    discard posix.kill(posix.getpid(), cint(signal))
+    waitFor(fut)
+    signalCounter == value
+
+else:
+  const
+    SIGINT = 0
+    SIGTERM = 0
+  proc test(signal, value: int): bool = true
+
+when isMainModule:
+  suite "Signal handling test suite":
+    test "SIGINT test":
+      check test(SIGINT, 31337) == true
+    test "SIGTERM test":
+      check test(SIGTERM, 65537) == true